Abstract 9518: Miscarriage and Risk of Atherosclerosis, A Nationwide Cohort Study of One Million Women

Abstract

Background: Atherosclerosis might share aetiology with adverse pregnancy events through metabolic and vascular pathology or inflammatory responses. Knowledge on risk of atherosclerotic diseases in women experiencing spontaneous abortion/miscarriage is limited. In this nationwide cohort study we aimed to examine risk of three different atherosclerotic conditions in women who had experienced miscarriage.

Methods: In Danish registers, we identified women experiencing a miscarriage or giving birth to a live singleton from 1977-2008. Women aged ≥12 years and free of cardiovascular disease were followed for incident cases of myocardial infarction, cerebral infarction and renovascular hypertension. Using Poisson-regression we estimated incidence rate ratios with 95% confidence intervals for these conditions by history of miscarriages.

Results: In 1,031,279 women followed for more than 15 million person-years, we identified 2,798 incident cases of myocardial infarction, 4,053 incident cerebral infarcts and 1,448 incident cases of renovascular hypertension. Incidence rate ratios with 95% confidence intervals (adjusted for age, calendar-period, and number of children) for one and ≥four miscarriages respectively compared to no miscarrriages, were 1.11 (1.00-1.23) and 2.08 (1.25-3.45) for myocardial infarction, 1.13 (1.03-1.23) and 1.89 (1.20-2.96) for cerebral infarction, and 1.15 (0.99-1.34) and 3.78 (2.08-6.85) for renovascular hypertension. Trends with 95% confidence intervals for step-wise increase in risk for the three conditions given one additional miscarriage was 9% (3-16%), 13% (7-19%) and 19% (9-30%), in those aged ≤32 years all trends rose to around 60%. Adjusting for smoking, diabetes mellitus, polycystic ovarian syndrome and thrombophilia left estimates unchanged. Similar strong and consistent trends were not observed for live birth history.

Conclusion: We found a consistent association between previous miscarriages and increased risk of myocardial infarction, cerebral infarction and renovascular hypertension. This is suggestive of shared aetiology in atherosclerosis and miscarriage, or possible pathological processes initiated by a miscarriage and leading to atherosclerosis.